Resins such as polypropylenes (PP), acrylonitrile-butadiene-styrene (ABS), polyamides (PA6, PA66), polyesters (PET, PBT) and polycarbonates (PC) are used as raw materials for obtaining resin molded articles. These resins are produced from raw materials obtained from oil resources. In recent years, problems such as the depletion of oil resources and global environment have been concerned, and the production of a resin from a raw material obtained from biogenic matter such as a plant has been desired. Especially when a global environmental problem is taken into consideration, a resin obtained from a plant-derived raw material is regarded as a resin having a low load on the global environment from the concept “carbon neutral” which means that the balance of carbon is neutral in view of the amount of carbon dioxide absorbed during the growth of a plant even when it is burnt after use.
Meanwhile, to use a resin obtained from a plant-derived raw material as an industrial material, especially an electric/electronic-related part, OA-related part or auto part, flame retardancy must be provided to the resin from the viewpoint of safety.
Various attempts have been made for the flame retardation of resins obtained from plant-derived raw materials, especially polylactic acid resin, and a certain measure of flame retardation has been achieved. However, a large amount of a flame retardant is used to flame retard these resins, whereby the physical properties of the resins are impaired.
Meanwhile, as a resin obtained from a plant-derived raw material, a polycarbonate resin prepared from a raw material obtained from an ether diol residue which can be produced from sugar is now under study, in addition to the polylactic acid resin.
For example, an ether diol represented by the following formula (a) is easily produced from sugar or starch, and three stereoisomers of the ether diol are known.

In concrete terms, the stereoisomers are 1,4:3,6-dianhydro-D-sorbitol (to be referred to as “isosorbide” hereinafter in this text) represented by the following formula (b),
1,4:3,6-dianhydro-D-mannitol (to be referred to as “isomannide” hereinafter in this text) represented by the following formula (c),
and 1,4:3,6-dianhydro-L-iditol (to be referred to as “isoidide” hereinafter in this text) represented by the following formula (d).

Isosorbide, isomannide and isoidide are obtained from D-glucose, D-mannose and L-idose, respectively. For example, isosorbide can be obtained by hydrogenating D-glucose and dehydrating it with an acid catalyst.
Heretofore, it has been studied to incorporate especially isosorbide among the above ether diols into a polycarbonate as the main monomer. Particularly isosorbide homopolycarbonates are disclosed by Patent Documents 1 and 2.
Patent Document 1 reports a homopolycarbonate resin having a melting point of 203° C. which is produced by a melt transesterification process. However, this polymer has unsatisfactory mechanical properties.
As an example having high heat resistance, Patent Document 2 reports a polycarbonate having a glass transition temperature of 170° C. or higher measured by differential calorimetry at a temperature elevation rate of 10° C./min. However, it has a high reduced viscosity and involves a problem that its melt viscosity is too high when it is considered as a molding material.
Meanwhile, Patent Document 3 discloses a copolycarbonate of isosorbide and a linear aliphatic diol.
The flame retardancies of the polycarbonates obtained from isosorbide are not studied at all in all of these documents.    (Patent Document 1) UK Patent Laid-opened publication No. 1079686    (Patent Document 2) WO2007/013463    (Patent Document 3) WO2004/111106